From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1INdBH-0000KD-Fw for qemu-devel@nongnu.org; Tue, 21 Aug 2007 19:30:39 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1INdBF-0000GW-P4 for qemu-devel@nongnu.org; Tue, 21 Aug 2007 19:30:38 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1INdBF-0000GB-Hu for qemu-devel@nongnu.org; Tue, 21 Aug 2007 19:30:37 -0400 Received: from zero.voxel.net ([69.9.191.6]) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1INdBF-00030t-Ir for qemu-devel@nongnu.org; Tue, 21 Aug 2007 19:30:37 -0400 From: Matthew Kent Content-Type: text/plain Date: Tue, 21 Aug 2007 16:30:32 -0700 Message-Id: <1187739032.2562.85.camel@fuego> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] linux verify_pmtmr_rate() issue Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kvm-devel@lists.sourceforge.net Issue here that's beyond my skill set to resolve: I've been starting multiple linux 2.6.23-rc3 x86 guests up in parallel with qemu/kvm and noticed pm-timer is being disabled in some of them with PM-Timer running at invalid rate: 126% of normal - aborting. in dmesg when I start about 6 at a time. Unfortunately without the timer a tickless kernel in my guests is disabled. I also replicated the issue by starting a single vm when the host system was busy enough. After some amateurish debugging added to verify_pmtmr_rate() in the kernel acpi_pm driver and get_pmtmr() in qemu acpi I can indeed see it returning just slowly enough to throw off the sanity check. [ 10.264772] DEBUG: PM-Timer running value1: 2925874 value2: 3058371 expected_rate: 107385 delta: 132497 count: 2269 [ 10.270766] PM-Timer running at invalid rate: 123% of normal - aborting. For now I've just disabled verify_pmtmr_rate() in the kernel for my guests and they seem to be keeping time just fine. Not sure if a patch for the linux kernel making the sanity check optional with a kernel parameter would make sense or there's something else that can be done at the qemu level. Thanks. -- Matthew Kent http://magoazul.com